One day I was asked to look at MikroTik CRS106-1C-5S, whose users could not use the Internet normally, there was no speed and ping requests dropped out. When I looked at CPU utilization, it was almost 100% (in the menu System – Resources).Continue reading “Solution for heavy CPU load MikroTik CRS106-1C-5S”
I will show an example of running iPerf to test network bandwidth using UDP Multicast.Continue reading “iPerf Mulicast”
Starting with Zabbix 6.0, primary keys are used for all tables in new installations, but since I upgraded Zabbix server to version 6.4, I had to manually update the tables after the upgrade.
Before updating, first of all, open the menu “Report” – “System Information” and make sure that the keys are not used, this will be indicated by the entry – “Database history tables use primary key – No”, if the keys are used, then this entry simply will not be.Continue reading “Zabbix. Upgrading the database to primary keys”
Once I found the following messages in the dmesg log:Continue reading “Messages net_ratelimit: X callbacks suppressed”
I will give the script code from Intel to bind interrupts of Intel network adapters to processor cores, and also show examples of its use:Continue reading “Script to bind Intel NIC interrupts to processor cores”
By default, processes use all the processor cores, but sometimes it is necessary to release the 0 core, which is usually the most loaded, or assign some processes only to the second CPU, etc., in this case, taskset will help.Continue reading “Taskset – bind process to CPU cores”
There is a possibility that on a highly loaded server, such as a proxy or router, with a very large number of connections, free ports in the allocated range may run out, so you need to look at the current number used and, if necessary, increase the net.ipv4.ip_local_port_range value.Continue reading “Increase the port range net.ipv4.ip_local_port_range”
Logrotate is used to control the logging system, compress log files, delete old ones, etc.
The configuration is located at /etc/logrotate.d/ and /etc/logrotate.conf.
dhcpperf is a DHCP load testing tool.Continue reading “Testing a DHCP server with dhcpperf”
innodb_flush_method defines the method for flushing data from RAM to disk.Continue reading “How to change innodb_flush_method in MySQL”